January 2, 2008

DNA clues on the African origin of Chinese populations

Modern man, or Homo sapiens, might have migrated from Africa into China by way of Southeast Asia between 18000 and 60000 years, researchers say.

This latter finding, the search for Chinese scientists and their international colleagues concluded that modern humans might have moved from Africa to China to replace Mono erectus (archaic of walking upright human beings) , to become the ancestors of the country \ 'modern man.

The conclusion is based on the comparison and analysis of the Y chromosome using DNA samples of 88 existing populations in East Asia, Southeast Asia and Oceania , said Li Jin, one of the Chinese researchers of the study "Chinese Human Genome Diversity Project. \ "

Li Jin is a professor of both the National Human Genome Center in Shanghai and the Institute of Genetics, Fudan University.

Scientists have found that variations in the Y chromosome in northern China are derived from those in the south of China, the fact that a small number of settlers of African origin moved to the north of China because of the obstacle of the powerful Yangtze River. And Polynesians, who live in the islands of the Pacific Ocean, are found to have different Y chromosome in Taiwan, forcing scientists to reconsider the hypothsis that Polynesians are the descendants of the ancestors of Taiwanese aborigines.

In general, almost all Y-chromosome variations in East Asia and Oceania could be found among those in Southeast Asia, said Li Jin.

Therefore, the results also indicate that modern humans migrated from Africa to Southeast Asia almost 60000 years.

Subsequently, the migrants are believed to have headed for two directions: one moved north to the south of China before spreading in the country \ 's north across the river Yangtze, and the other went to Indonesia and finally reached the Oceania.

The Y-chromosome research is an important method for tracing the migration patterns of men and the results clearly show the relationships between groups of people in Southeast Asia and Asia and 'Oceania, according to another major Chinese researcher Jiayou Chu, a professor of the Chinese Academy of Medical Sciences.

The research result was published in today \ 's issuance of the Proceeding of National Academy of Sciences, an American journal.

The finding means that scientists have made progress in the pursuit of human origin, though the conclusion that human beings modern Chinese migrated from Africa remains controversial, "said Academician of the Academy Science Chinese Zhu Chen, who is also the director of Shanghai \ 'S National Human Genome Center.

In 1987, the United States \ 'scientists postponed a theory based on mitochondrial DNA evidence that all human beings from Africa and later migrated to other corners of the globe. Intentional in academia, few arguments were raised about the theory that all humanity palaeoanthropic originated in Africa. Meanwhile, scientists noted that the fossils of Peking Man who lived 500000 years ago and Yuanmao Man more than 1.7 million years old have been discovered in China, but both lack any direct link with hereditary Chinese modern man.

There is a disconnection or "faultage" in the fossil palaeoanthropic Chinese who lived some 60000 to 100000 years, researchers say.

Coinciding with the fossil record, Chinese scientists discovered last year that primitive elements of DNA found in modern Chinese are identical to those found in Africans.

The discovery has provided evidence of weight on the genetic basis of the theory that modern Chinese were not changed since the archaic-walking upright human beings in China, but from Africa.